Thrust reversers are provided on a gas turbine engine to selectively alter the direction of the fan flow from the engine. The thrust reversers are typically deployed on landing to decelerate an aircraft and sometimes used for power-back of the aircraft.
One type of thrust reverser is known as a cascade thrust reverser that has an array of cascade boxes downstream of a fan casing that are deployed by an axial rearward translation of a trans cowl that causes blocker doors to rotate from a stowed position to their deployed position and direct the bypass duct air radially outwards, through the cascades. Each cascade box has a plurality of guide vanes to turn the air.
In order to prevent lift being generated on opening of the cascade it is possible to provide a blanking cascade towards the bottom of the engine. The blanking cascade inhibits the flow of air under the engine. In alternative arrangements for efflux control specially oriented guide vanes may be used to better control the direction of outflowing air.
Engine efficiency is driven partly by the weight of the engine, including the nacelle and thrust reverser, and it is an object of the invention to seek to provide an improved thrust reverser arrangement.